More than a week since the failure of China's biggest private investment in Russia, Beijing has given no explanation for the collapse of the deal.

On May 4, Swiss-based trader Glencore plc announced it had cancelled its agreement with the Qatar Investment Authority (QIA) to sell most of their shares in Russia's Rosneft oil company to privately-held CEFC China Energy Company Ltd. for U.S. $9.1 billion (57.9 billion yuan).

The breakdown of the blockbuster deal came nearly eight months after the sale of a 14.16-percent stake in state-controlled Rosneft was unveiled last September and eight days after a CEFC official said the agreement could still be saved.

In between those times, speculation ran rampant over the whereabouts of CEFC's mysterious founder Ye Jianming, who was reportedly detained for questioning in March, and how his little-known firm could have grown so large and so fast that it could capture a share of the biggest oil producer in the world.

Now, with the collapse of the deal, new questions have also gone unanswered.

Did CEFC ever have government support for its bid to invest in Rosneft?

If so, why did China's government turn against CEFC and its part in the deal?

Whether it ever backed CEFC or not, why didn't the government step in to rescue the sale and gain access to the Russian oil industry for a Chinese national oil company (NOC) or a state investment group?

And what does the decision against making a major investment in Russia say about relations with China and concerns about financial risks?

Definitive answers may never be known, but Rosneft's statement on QIA's decision to take back nearly all of the 19.5 percent of shares it held in the consortium with Glencore since 2016 suggests that the oil company was left seeking answers, as well.

"The company has (nothing to do) with the changes in the holding structure of the Glencore-QIA consortium, but at the same time Rosneft supports the decision of its stockholders to switch to the direct possession of shares," said the statement, according to Russia's Sputnik news service.

Rosneft said that "the Chinese market remains to be strategic for the development of the company's business," but it had nothing to say about CEFC or China's decision to pass up the investment opportunity.

News met with silence

News of the deal's failure was met with silence from the governments in Beijing and Moscow.

"There is still virtually no official information," Russia's Interfax news agency said in a summary report.

The absence of confirmed answers appears to stem from China's opaque government policies on foreign investment and financing, compounded by corruption charges against a CEFC official that surfaced six months ago.

Numerous reports have drawn links between Ye's disappearance and U.S. bribery charges against former Hong Kong home affairs secretary Patrick Ho Chi-ping in a case involving African oil rights.

Until his arrest in New York in November, Ho headed the China Energy Fund Committee, a CEFC affiliate.

The case has been seen as an embarrassment for President Xi Jinping's signature "One Belt, One Road" (OBOR) trade expansion initiative, casting a pall of silence over the whole CEFC affair.

Whether that is an explanation for the lack of clarity over the Rosneft deal or not, it sheds little light on China's apparent decision against replacing CEFC with a state-owned NOC, giving it a share in China's leading oil supplier.

In April, state-run investment conglomerate CITIC Group announced plans to take a 49-percent stake in CEFC Europe, based in the Czech Republic, raising expectations of a similar rescue for the oil deal. But none has materialized.

The cancellation of the sale has had major consequences for Rosneft.

Last week, Reuters reported that QIA had pressed the company for higher returns before it agreed to take back the consortium's shares.

The demand led Rosneft's CEO Igor Sechin to propose a U.S. $2-billion (12.7-billion yuan) share buyback and a debt reduction of U.S. $8 billion (50.7 billion yuan), impacting its corporate strategy, according to Reuters.

China's decision to forego the investment opportunity is all the more remarkable in light of past efforts to break into the Russian petroleum industry since the two countries signed a friendship treaty in 2001.

Russia resisted China's overtures for years and only gradually lowered its investment barriers after major Chinese financing and supply deals allowed Rosneft to expand starting in 2004.

Other reports have also tried to explain the collapse of the CEFC deal in terms of China's tougher restrictions on outbound investments since 2016 as part of the government's efforts to curb capital outflows and financial risks.

But that explanation also poses a puzzle. China's policy specifically targets investments in sectors including real estate, hotels and sports clubs.

Although CEFC Europe has investments in each of those sectors, CITIC has stepped in to shore up support. Last week, Reuters reported separately that CITIC has promised to cover some 450 million euros (3.4 billion yuan) of CEFC Europe's debt.

China has placed no similar restrictions on foreign oil investments, yet the government has mounted no effort to rescue the landmark Rosneft deal.

While China appeared to back away from the Rosneft investment, it has been plunging ahead elsewhere.

On Friday, China Three Gorges Corp. (CTG) launched a bid to take control of Portugal's leading utility Energias de Portugal (EDP) for 9.1 billion euros (68.8 billion yuan), news agencies reported.

CTG already owns 23 percent of EDP. The bid suggests that China is still eager to make other strategic investments abroad.

The contradictions are only part of the uncertainties that have clouded the CEFC sale since it was announced in September, said Edward Chow, senior fellow for energy and national security at the Center for Strategic and International Studies in Washington.

Although there has been little confirmed information, a logical thread may connect some of the dots about why the deal failed.

The new questions that have arisen since the cancellation can't be answered until more is known about how CEFC emerged as a buyer of the Rosneft shares in the first place, Chow said.

"This guy Ye was clearly very well connected," said Chow.

"He would not have been allowed to do all the things he's done, first domestically and then internationally, without being very connected. Who knows what his connections are, but it strikes me as being pretty high-level," he said.

But suddenly, the assumptions about Ye's connections were called into question with the arrest of Patrick Ho.

"Then, he (Ye) became an embarrassment, and maybe he became an embarrassment even before Patrick Ho was picked up in New York, but certainly that exacerbated the problems," Chow said.

The charges raised doubts about the rapid rise of CEFC and the dozens of deals that it made to expand with easy credit from state banks.

"They were able to do these things because of access to easy money, ... and then it all dried up," Chow said.

'Story that no one wants to talk about'

CEFC's troubles coincided with China's reassessment of financial risks, debt growth and foreign investment, leading to pressures on high-flying conglomerates like HNA Group Company Ltd. and Anbang Insurance Group, and a potential loss of confidence in China's commitments.

"There's a story inside China that no one really wants to talk about," Chow said.

While Russian state lender VTB Bank offered interim financing for the Rosneft sale, CEFC's biggest financing source, China Development Bank, said in March that it was never even approached.

The mysteries surrounding Ye's spectacular rise and sudden fall may have made it difficult for a Chinese NOC or financial group to simply step in to replace CEFC. A longer period of due diligence would have been needed to assess the risks, Chow said.

That doesn't mean that China won't eventually come back to investing in Rosneft if the opportunity comes around again. But the questions surrounding CEFC may make it impossible now.

Given the conditions, it may be too soon to draw conclusions about what the failed deal means for relations between Russia and China.

"It turned out that CEFC was the wrong vehicle to cement that relationship," said Chow.

"I don't discount the possibility that it could still happen," he said. "If I wake up some day next year and it turns out that some Chinese company has bought 10 percent of Rosneft, I would not be shocked."